The present invention relates to an X-ray irradiator and an X-ray imaging apparatus. Particularly, the present invention is concerned with an X-ray irradiator for irradiation of X-rays from an X-ray tube through a collimator, as well as an X-ray imaging apparatus using the X-ray irradiator.
In an X-ray imaging apparatus, X-rays are radiated to a subject while limiting an irradiation field by means of a collimator. The collimator is housed within a collimator box attached to an X-ray tube (see, for example, Patent Literature 1).
[Patent Literature 1] Japanese Unexamined Patent Publication No. 2003-61941 (page 3, FIG. 1)
A certain object requires to be photographed in an appropriately rotated state of a collimator box relative to an X-ray tube. When the collimator box is rotated, a frame of a display image also rotates. For correcting this state to obtain an erected image frame constantly, it is necessary to detect a rotational angle of the collimator box.